Crystalline modifications of N-α-(2,4,6-triisopropyl-phenylsulfonyl)-3-hydroxyamidino-(L)- phenylalanine 4-ethoxycarbonylpiperazide and/or salts thereof

ABSTRACT

The present invention relates to novel crystalline modifications of N-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine 4-ethoxycarbonylpiperazide and/or salts thereof, which can be used as pharmaceutical agents, and to pharmaceutical compositions and pharmaceutical uses comprising these novel crystalline modifications.

CROSS REFERENCE TO RELATED APPLICATION

This application is a 35 USC 371 National Phase Entry Application fromPCT/EP2005/012589, filed Nov. 24, 2005, and designating the UnitedStates.

The present invention relates to novel crystalline modifications ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide and/or salts thereof, which can be used aspharmaceutical agents, and to pharmaceutical compositions andpharmaceutical uses comprising these novel crystalline modifications.

The novel crystalline modifications of the present invention, whichstart from a compound which is known under the chemical nameN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide, are efficacious inhibitors of serineprotease urokinase and therefore particularly suitable for the treatmentof urokinase-associated disorders, such as, for example, tumors andmetastases, in particular for oral use. The free base form is designatedas WX-671.

The plasminogen activator of the urokinase type (uPA) plays a key rolein tumor invasion and formation of metastases (Schmitt et al., J. Obst.Gyn. 21 (1995), 151-165). uPA is expressed in the most different typesof tumor cells (Kwaan, Cancer Metastasis Rev. 11 (1992), 291-311) andbinds to the tumor-associated uPA receptor (uPAR), where the activationof plasminogen to plasmin takes place. Plasmin is able to break downvarious components of the extracellular matrix (ECM), such asfibronectin, laminin and collagen type IV. It also activates some otherECM-degrading enzymes, in particular matrix metalloproteinases. Highamounts of tumor-associated uPA correlate with a higher risk ofmetastasis for cancer patients (Harbeck et al., Cancer Research 62(2002), 4617-4622). Inhibition of the proteolytic activity of uPA istherefore a good starting point for an antimetastatic therapy.

A few active and selective urokinase inhibitors have already beendescribed. Thus, uPA inhibitors of the benzamidine type are disclosed inEP 1 098 651, uPA inhibitors of the arylguanidine type in WO 01/96286and WO 02/14349. A common feature of these synthetic inhibitors is abasic residue consisting of an amidino or/and guanidino group.

International patent application WO 03/072559 discloses WX-671 as anintermediate in the synthesis of the urokinase inhibitorN-α-(2,4,6-triisopropylphenylsulfonyl)-3-amidino-(L)-phenylalanine4-ethoxycarbonylpiperazide. WO 03/072559 also discloses a process forthe preparation of the compound WX-671 as a free base or in the form ofits salts formed with acids. Special salts, in particular thehydrogensulfate and the sulfate form, are not mentioned. Process forcrystallization are likewise not described. In the processes described,the free base WX-671 is obtained as an amorphous product, which isthermally slightly unstable and hygroscopic and which has unsuitablefiltration and drying properties. For this reason, it is not suitablefor preparation on a large scale and must be especially protected fromheat and moisture.

WO 2004/011449 likewise discloses processes for the preparation ofphenylalanine derivatives, which can also be present as salts, e.g. assalts of mineral acids or as salts of organic acids. One of thecompounds prepared is WX-671. Here too, no indication is given of thefact that the compounds disclosed can also be obtained in a stablecrystalline form.

PCT/EP2004/005682 discloses hydroxyamine and hydroxyguanidine compoundsas urokinase inhibitors. The medicaments disclosed comprise as activecompound, inter alia, WX-671 and the active compounds can be present assalts, e.g. as hydrochloride or hydrogensulfate or as salts of organicacids. A better bioavailability on oral administration was asserted forthe medicaments claimed there. This publication too, however, does notdisclose any sulfate salt compound of said urokinase inhibitors.

The object of the present invention was the preparation of crystallinemodifications ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide and/or salts thereof, which have advantageousproperties compared to the compounds of the prior art.

The present invention provides crystalline modifications ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide and/or salts thereof.

According to the present invention, novel crystalline modifications ofthe abovementioned urokinase inhibitor were found which have crucialadvantages compared to the amorphous form of this compound. Thecrystalline modifications according to the invention have importantadvantages in handling, storage and formulation.

Surprisingly, the compoundN-α-(2,4,6-triisopropyl-phenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide and/or salts thereof can be crystallized,which was not possible hitherto, and is therefore superior in itsproperties to the amorphous compounds from the prior art. Thus thecrystalline modifications according to the invention are distinguishedby very low hygroscopicity. They are moreover very resistant todecomposition and are therefore also suitable for longer storage. Inaddition, the crystalline modifications according to the invention haveimproved filtration and drying properties. Moreover, the crystallinemodifications ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide and its salts are ideally suitable forformulation in pharmaceutical compositions.

As used herein, WX-671 means the free base ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide. WX-671.1 designates the hydrogensulfate ofsaid compound and WX-671.2 designates the sulfate of said compound.

As already mentioned at the outset, the modifications of WX-671according to the invention and salts thereof are essentiallycrystalline. Hitherto, it was not possible to prepare hydroxyamidinecompounds of this type in crystalline form. Even the compounds alreadydisclosed in the prior art were not crystallizable.

The crystalline modifications, according to the invention ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide and its salts preferably include thehydrogensulfate salt (WX-671.1) and the sulfate salt (WX-671.2), and thefree base (WX-671).

The crystalline modifications according to the invention can includemixtures of the free base and of the salts or alternatively mixtures ofthe salts. Preferably, the crystalline modification according to theinvention in each case includes either the free base or the sulfate saltor the hydrogensulfate salt as a crystalline modification. Particularlypreferably, the crystalline modification according to the inventionincludes single crystals of the respective crystalline modification.

The crystalline modifications according to the invention wereinvestigated by X-ray diffractometry and preferably have the peaks shownin Table 3.1 (for the sulfate salt WX-671.2), Table 7.1 (for thehydrogensulfate salt WX-671.1) and Table 11.1 (for the free base). Thecrystalline modifications according to the invention essentially havethe peaks shown in FIG. 5 (for the sulfate salt WX-671.2), 13 (for thehydrogensulfate salt WX-671.1) and 19 (for the free base).

As is described in the examples below, additionally to the X-raydiffractometry analyses, thermoanalytical investigations were alsocarried out (differential scanning calorimetry, DSC andthermogravimetry, TGA). It was seen here that the crystalline compoundof the hydrogensulfate salt WX-671.1 decomposes at a temperature ofapproximately 175° C.-195° C., more precisely in the range fromapproximately 185° C. (at a heating rate of 2 Kmin⁻¹).

The crystalline modification of WX-671.2 according to the inventionpreferably containsN-α-(2,4,6-tri-isopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide and sulfate anions in a molar ratio ofapproximately 2:1, where this ratio can vary in a range from 1.5 to2.5:1. A ratio of approximately 1.25 to 2.25:1 is preferred, more highlypreferably 1.1 to 2.1:1 and most highly preferably in the ratio ofapproximately 2:1.

The crystalline modification of WX-671.2 preferably has units of in eachcase 2 molecules ofN-α-(2,4,6-tri-isopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide and a sulfate anion, where in each of theseunits the 2 molecules ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide can be present in the same conformation orthey can preferably also be present in different conformations.

In addition, the crystalline modification of WX-671.2 is preferablypresent as a hydrate, in particular as a trihydrate, i.e. per mole ofsalt approximately 3 mol of water are present. This ratio can, ofcourse, also be subject to slight variations, i.e. per mole of salt onaverage between 2.5 and 3.5 mol of water can be present, preferablybetween 2.25 and 3.25, more highly preferably between 2.2 and 3.2, morehighly preferably between 2.1 and 3.1.

The sulfate salt ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide has, independently of the crystallinity,turned out to be the thermodynamically stable compound. Therefore thepresent invention also provides the novel compound ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide sulfate salt. The noncrystalline sulfate saltWX-671.2 is also suitable, as described below for the crystallinemodifications, for the production of medicaments.

In the crystalline modification of WX-671.1,N-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide and hydrogensulfate anions are preferablypresent in a molar ratio of 0.5 to 1.5:1, more highly preferably of 0.8to 1.2:1, more highly preferably 0.9 to 1.1:1, more highly preferablyapproximately 1:1.

A crystalline modification of WX-671.1 can also be present as a hydrate.

The crystalline modification of WX-671 (free base) is preferably notpresent as a hydrate. A hydrate form is, however, possible.

The crystalline modifications according to the invention can optionallybe used with suitable pharmaceutical excipients and/or vehicles for theproduction of medicaments. Here, administration in combination withother active compounds, e.g. other urokinase inhibitors, such as, forexample, antibodies and/or peptides, but also with chemotherapeutics andcytostatics or/and other cytostatic and cytotoxic active compounds ispossible.

The crystalline modifications according to the invention can thus beprepared in a suitable pharmaceutical formulation, for example astablets, coated tablets, capsules, pastilles, powder, syrup, suspension,solution or the like. In particular, a pharmaceutical preparation fororal administration is preferred.

The crystalline modifications according to the invention are suitablefor the control of diseases which are associated with a pathologicaloverexpression of uPA or/and urokinase plasminogen activator receptor(uPAR). It is, for example, able to inhibit the growth or/and the spreadof malignant tumors and the metastasis of tumors highly efficiently.Examples of this are oncoses, e.g. breast cancer, lung cancer, bladdercancer, stomach cancer, cervical cancer, ovarian cancer, kidney cancer,prostate cancer and soft tissue sarcomas, in particular tumorsassociated with a high metastasis rate.

The modifications according to the invention can be employed on theirown or in combination with other physiologically active substances, e.g.with radiotherapeutics or with cytotoxic or/and cytostatic agents, e.g.chemotherapeutics, such as, for example, cis-platin, doxorubicin,5-fluorouracil, taxol derivatives, or/and other chemotherapeutic agents,for example selected from the group consisting of the alkylating agents,antimetabolites, antibiotics, epidophyllotoxins and vinca alkaloids. Acombination with radiation therapy or/and surgical interventions islikewise possible.

Furthermore, the crystalline modifications according to the inventionare also efficacious for other uPA-associated diseases. Examples ofdiseases of this type are, for example, pulmonary high blood pressureand/or heart diseases (e.g. WO 02/00248), gastric and bowel diseases,such as, for example, inflammatory bowel diseases, premalignant colonadenomas, inflammatory diseases, such as, for example, septic arthritis,or other diseases, such as osteoporosis, cholesteatomy, skin and eyediseases, such as, for example, age-related macular degeneration (AMD),and viral or bacterial infections, reference being made expressly to thediseases mentioned in EP-A-0 691 350, EP-A-1 182 207 and U.S. Pat. No.5,712,291.

A further subject of the present invention is a medicament whichincludes a crystalline modification according to the invention as anactive compound. Such a medicament can optionally additionally includepharmaceutically tolerable carriers and/or excipients. The medicamentscan be administered to man or animals topically, orally, rectally orparenterally, e.g. intravenously, subcutaneously, intramuscularly,intraperitoneally, or alternatively sublingually, nasally and/orinhalatively. Suitable administration forms are, for example, tablets,coated tablets, capsules, pastilles, pellets, powder, suppositories,solutions, syrup, emulsions, suspensions, liposomes, inhalation spraysor transdermal systems, such as, for example, patches. A particularlypreferred pharmaceutical compositions is suitable for oraladministration, e.g. also as a slow-release depot.

In addition, the present invention provides a use of the crystallinemodifications according to the invention for the production ofpharmaceutical composition for the control of diseases which areassociated with a pathological overexpression of urokinase and/or theurokinase receptor. In particular, such a medicament containing theactive compound according to the invention is suitable for tumortreatment and/or prevention and in particular also for the treatment orprevention of formation of metastases, and for the treatment of primarytumors and secondary tumors.

By means of the present invention, one possibility for urokinaseinhibition in living beings, in particular man, is provided byadministration of an efficacious amount of the modification according tothe invention. The dose to be administered depends on the nature andseverity of the diseases to be treated. For example, the daily dose isin the range from 0.01-100 mg/kg of active substance per body weight,more highly preferably 0.1-50 mg/kg, more highly preferably 0.5-40mg/kg, more highly preferably 1-30 mg/kg, more highly preferably 5-25mg/kg.

A further subject of the present invention is a process for theproduction of an essentially crystalline modification of anN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide salt, comprising the steps:

-   (a) preparation of the compound    N-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine    4-ethoxycarbonylpiperazide or of one of its salts,-   (b) dissolution or/and suspension of the compound or of the salt    itself from step (a) in a solvent suitable for the formation of the    crystalline modification,-   (c) separation of the crystalline modification.

It has surprisingly been shown that the crystalline modifications ofWX-671, WX-671.1 and WX-671.2 can be prepared in crystalline form in asimple manner. Preferably, the starting material used is a salt ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide, particularly preferably the hydrogensulfatesalt.

However, other salt compounds are also suitable as starting compoundsfor the formation of crystalline modifications, for example the besylatesalt, hydrochloride salt, mesylate salt, tartrate salt and others.

Solvents used for step (b) can preferably be various organic solvents.Those suitable are, for example, water and various alcohols, e.g.methanol, ethanol, propanol, butanol and their isoforms, such as, forexample, isopropanol, isobutanol etc., and furthermore glycols, ethers,glycol ethers, acetone and the like. Further suitable solvents aretetrahydrofuran (THF) and acetonitrile. Preferred solvents are inparticular acetone and acetonitrile.

However, water can also be used as a solvent. In particular for therecrystallization (see step (d)), water is preferably used.

If the free base is used as a starting material for the preparation of acrystalline modification of a salt ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide, suitable salts or acids are additionallyadded in step (b) in order to obtain the respective desired salt ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide.

The process according to the invention can also include a further step(d) of recrystallizing the crystalline compounds from step (c). Thisapplies in particular for the preparation of WX-671.2 from WX-671.1.Here, the crystalline modification resulting in step (c) is in turnpreferably recrystallized in a suitable solvent or a mixture ofsolvents. Here too, as solvents those mentioned beforehand can beemployed. In particular, water is preferred, or recrystallization ispreferably carried out with a content of water sufficient for theformation of the desired crystalline modification. Water is preferred inparticular if, as, for example, in the case of WX-671.2, a hydrate (inthe case of WX-671.2 a trihydrate) is formed.

The invention will now be illustrated in more detail by the followingfigures and the examples.

DESCRIPTION OF THE FIGURES

FIG. 1 shows an Ortep plot (50%) with symbol plot for molecule A(WX-671.2).

FIG. 2 shows an Ortep plot (50%) with symbol plot for molecule B(WX-671.2).

FIG. 3 shows independent molecules within a unit cell of a unit of twomolecules of WX-671.2 and sulfate anion.

FIG. 4 shows a simulated X-ray diffractogram using single crystal dataof WX-671.2.

FIG. 5 shows an experimental X-ray diffractogram of WX-671.2.

FIG. 6 a shows the superimposition of the simulated X-ray diffractionpattern and of the experimental X-ray diffraction pattern according toFIGS. 4 and 5 for WX-671.2.

FIG. 6 b shows the DSC and TGA thermograms of WX-671.2 after stirring inwater.

FIG. 7 lists the crystal data and structure refinement for WX-671.2.

FIG. 8 shows the bond lengths [Å] and angles [°] for WX-671.2.

FIG. 9 shows the torsion angles [°] for WX-671.2.

FIG. 10 shows the DSC and TGA thermograms of WX-671.1 (modification A).

FIG. 11 shows the DSC and TGA thermograms of a sample (mesophase B) ofWX-671.1.

FIG. 12 shows the DSC and TGA thermograms of mesophase C of WX-671.1.

FIG. 13 shows the X-ray diffractogram of modification A of WX-671.1.

FIG. 14 shows the X-ray diffractogram of mesophase B of WX-671.1.

FIG. 15 shows the X-ray diffractogram of mesophase C of WX-671.1.

FIG. 16 shows the DSC and TGA thermograms of the amorphous startingsubstance of the free base WX-671.

FIG. 17 shows the DSC and TGA thermograms of a sample of the free baseWX-671 crystallized from acetonitrile in the freezer.

FIG. 18 shows a micrograph of the free base WX-671 after crystallizationfrom acetonitrile in the freezer.

FIG. 19 shows the X-ray diffractogram of the free base WX-671 aftercrystallization from acetonitrile in the freezer.

FIG. 20 shows the sorption isotherm of water vapor on the free baseWX-671 at 22° C.

EXAMPLES Example 1 Preparation of various salts ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide

The salts were prepared by dissolving 6.0 g of WX-671 in 50 ml ofacetone. The acids used were added in a 25% excess without dilution andthe mixture was stirred at room temperature for two hours.

Crystallization Conditions

TABLE 1.1 Acid Equivalent Crystallization conditions Drying HCl 1.25 moleq. Clear solution High vacuum H₂SO₄ 1.25 mol eq. Crystallized fromacetone High vacuum solution MsOH 1.25 mol eq. Crystallized from acetoneHigh vacuum solution BsOH 1.25 mol eq. Clear solution High vacuumTartaric 1.25 mol eq. Clear solution High vacuum acid

In a second step, the salts were suspended for 7 days in a suitablesolvent, filtered and dried at room temperature.

Investigation of the Crystallinity

Processes: X-Ray Diffractometry (XRD); Microscopy

TABLE 1.2 Species XRD Microscopy Free base mainly crystalline smallparticles Besylate mainly amorphous agglomerates Hydrochloridecompletely amorphous small particles Mesylate liquid crystallineagglomerates Hydrogensulfate liquid crystalline agglomerates Tartratecompletely amorphous glassInvestigation of the HygroscopicityProcess: Storage for 1 Week/85% Relative Humidity; ThermogravimetricAnalysis (TGA)

TABLE 1.3 Species TGA Free base 1.5% (semihydrate) Besylate 10.1%(adsorptive) Hydrochloride 7.5% (adsorptive) Mesylate 7.8% (adsorptive)Hydrogensulfate 0.8% (adsorptive) Tartrate 10.5% (adsorptive)

Example 2 Crystallization and Single Crystal X-Ray Structural Analysisof WX-671.2 (Sulfate Salt)

The novel form ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamidino-(L)-phenylalanine4-ethoxycarbonylpiperazide sulfate is obtained by suspending thehydrogensulfate salt (WX-671.1) of the compound WX-671 in water and byseparating off the crystalline compound formed.

Crystalline WX-671.2 was obtained in two different ways:

a) About 50 mg of WX-671.1 were suspended in about 0.5 ml of water. Thesuspension was allowed to stand at room temperature. After 6 days, thesuspension was filtered and the residue was dried in air at roomtemperature.

b) About 0.2 g of WX-671.1 was suspended in about 2 ml of water. Thesuspension was shaken at 25° C. After 3 days, the residue was filteredoff and the crystals of WX-671.2 were dried in air at room temperature.

The X-ray structure of the crystalline material (WX-671.2) prepared herewas determined. Single crystals were also obtained here.

The crystal structure determination was carried out using aBruker-Nonius diffractometer equipped with a Proteum CCD surfacedetector, an FR591 rotating anode with CuKα radiation, Montel mirror asa monochromator and a Kryoflex low temperature apparatus (T=90K). Fullsphere data determination omega and phi scans. Programs used: Proteumdata collection V.1.37 (Bruker-Nonius 2002), data reduction Saint+version 6.22 (Bruker-Nonius 2001) and absorption correction SADABSV.2.03 (2002). Crystal structure resolution was achieved by means ofdirect methods as implemented in SHELXTL version 6.10 (Sheldrick,University of Göttingen) and visualized by means of XP program.

Missing atoms were located by means of differential Fourier synthesisand added to the atom list. “Least squares refinement” on F2 over allmeasured intensities were performed using the program SHELXTL version6.10 (Sheldrick, University of Göttingen, 2000). All non-hydrogen atomswere “refined” with the inclusion of the “anisotropic displacementparameters”.

TABLE 2.1 Chirality Check* Correct Inverted structure structure Flackparameter (standard deviation) 0.0298 0.9694 (0.0282) (0.0307) Twin Basf(standard deviation) 0.03 (3) 0.97 (3) wR2 value (with Flack parameter)0.2016 0.2219 Chirality S(C9) R(C9) *H. D. Flack, Acta Cryst., 1983,A39, 876-881 H. D. Flack, G. Bernardinelli, Acta Cryst., 1999, A55,908-915 H. D. Flack, G. Bernardinelli, J. Appl. Cryst., 2000, 33,1143-1148

The results of the X-ray structural analysis are shown in FIGS. 1 to 3and 7 to 9.

Example 3 X-Ray Diffractometry of WX-671.2 (Sulfate Salt)

X-ray diffractograms were obtained using a STOE STADI-P Debye-Scherrerdiffractometer, equipped with a position-sensitive detector (PSD, 5°), agermanium [1 1 1] primary monochromator and a CuKα 1.6 kW ceramic X-raytube (1.5406 Å). Program used: Stoe WinXpow, version 2.03 (2003).

TABLE 3.1 X-ray diffractometry peak list for WX-671.2 WX 671.2Reflections 2 theta 3.7 4.2 7.1 7.4 10.3 10.8 11.1 11.6 12.1 12.6 13.313.8 14.2 14.8 15.1 15.7 16.4 16.8 17.3 17.8 18.0 18.6 19.2 19.8 20.120.4 20.8 21.0 21.2 21.8 22.2 22.9 23.4 23.9 24.6 25.0 25.5 26.2 26.326.5 26.8 27.2 27.5 27.8 28.1 29.1 29.7 30.2 30.6 31.1 31.4 31.9 32.133.2 33.8 34.2 36.3 37.3

Example 4 Recrystallizations of WX-671.1 (Hydrogensulfate Salt)

WX-671.1 was dissolved in solvents (isopropanol, ethanol, methanol) ofdifferent polarity. The solutions were filtered, divided into four, andthe solvents were removed at different rates.

WX-671.1 exists in its crystalline form (modification A) and twomesophases B and C. It decomposes from about 185° C. (modification A andmesophase B) or 156° C. (mesophase C). For the demonstration of thecrystallinity of modification A, an X-ray structure determination iscarried out. Modification A is the thermodynamically stable form at roomtemperature.

Example 5 Differential Scanning Calorimetry (DSC) and Thermogravimetry(TGA) of WX-671.1 (Hydrogensulfate Salt)

In this example, thermograms were plotted by differential scanningcalorimetry (DSC) and thermogravimetry (TGA). FIG. 10 shows the DSC andTGA thermograms of the WX-671.1 (modification A) stirred in isopropanolat 25° C. for one week. It decomposes from about 180° C. (exothermicpeak in the DSC thermogram, mass loss in the TGA thermogram in thecorresponding temperature range). The decomposition temperatures arestrongly heating rate-dependent and were determined in the DSCcalorimeter at a heating rate of 2 Kmin⁻¹. The DSC table measurementsshown were recorded at a heating rate of 2 Kmin⁻¹. The decomposition iscorrespondingly recorded at higher temperatures.

At 150° C., no significant mass loss is recorded. The weakly pronouncedendothermic effect before the decomposition peak could be caused bypartial melting or partial conversion.

FIG. 11 shows the DSC thermogram of a sample of WX-671.1 (mesophase B)employed for this screening. Modification A and mesophase B arethermoanalytically identical. Mesophase A was obtained from isopropanol(room temperature/refrigerator) and ethanol (room temperature).

FIG. 12 shows the DSC and TGA thermograms of the active compound after acrystallization attempt from methanol at room temperature (mesophase C).It decomposes from about 156° C. (heating rate 2 Kmin⁻¹). Up to 175° C.,a mass loss of 4.5% is recorded. In the DSC thermogram, the endothermiceffect before the decomposition peak is missing. This form is present ina less ordered state than modification A and mesophase B. It is formedafter crystallization attempts from methanol (room temperature,refrigerator) and ethanol (refrigerator). Mass losses of between 4.5 and4.8% by weight were recorded in the samples. The stoichiometric valuefor the mass loss of 2 molecules of water per active compound moleculeis 4.7%. This form, however, is not a hydrate.

Example 6 Thermomicroscopy of WX-671.1 (Hydrogensulfate Salt)

Thermomicroscopic recordings of a sample of WX-671.1 were made (notshown). Agglomerates were observed which show no specific habit. Theactive compound decomposes with bubble formation from about 197° C.Differences to the decomposition temperature observed in the DSCcalorimeter come about due to the different heating rates. WX-671.1 isobtained in nonspecific form from solvents. The active compound showsdouble diffraction in some cases, as is characteristic of crystallineand mesomorphic substances.

Example 7 X-Ray Diffractometry of WX-671.1 (Hydrogensulfate Salt)

The X-ray diffractogram of modification A (FIG. 13) shows the pattern ofnumerous sharp peaks at higher 2-theta angles characteristic ofcrystalline phases. For the confirmation of the existence of acrystalline phase, further investigations, e.g. an X-ray structuralanalysis, are carried out.

In the X-ray diffractogram of mesophase B (FIG. 14), a sharp peak wasobserved at a 2-theta angle of about 5° and further reflections of lowintensity between about 8° and about 25°. The position and number of thepeaks is similar to those of modification A. The peak present at lowtheta angle indicates the presence of a remote arrangement of themolecules; the peaks of low intensity verify the presence of a closearrangement. It can be concluded from this that mesophase B is presentneither in crystalline nor in amorphous form, but presumably as amesophase.

The X-ray diffractogram of mesophase C (FIG. 15) likewise shows apattern characteristic of mesomorphic compounds: an intensive peak atlow 2-theta angle. The X-ray diffractogram verifies that mesophase C isnot a crystalline phase and because of the remote arrangement presentcannot be considered part of the amorphous phase. Comparison with theX-ray diffractogram of mesophase B shows that mesophase C presumablyforms a phase having a low degree of organization. An indication of thisis the strongly pronounced and more intensive reflections in mesophase Bbetween the 2-theta angles of about 8° and about 25°.

By stirring in isopropanol at room temperature for one week, mesophase Bchanges into modification A. It does not change due to stirring inwater:ethanol (1:1). It likewise does not alter due to mechanical stress(grinding in a mortar, compressing at 9 kbar).

TABLE 7.1 X-ray diffractometry peak list for crystalline modification ofWX-671.1 (hydrogensulfate salt) WX 671.1 Reflections 2 theta 4.3 8.610.1 10.3 10.6 11.0 11.2 11.3 11.6 12.0 12.3 13.8 14.8 15.9 17.5 17.719.3 19.7 20.2 21.0 21.4 21.7 21.9 22.6 23.3 24.0 25.8 26.9 27.4 28.029.7 30.8 31.3 32.2 33.3 35.5 37.1

Example 8 Recrystallizations of WX-671 (Free Base)

The active compound WX-671 is investigated for polymorphismthermoanalytically (DSC, TGA), by X-ray diffractometry and bycrystallizations from organic solvents. WX-671 crystallizes in onemodification (modification A). The active compound shows a very lowtendency for crystallization.

Modification A is the thermodynamically stable form at room temperature.A final assessment of the polymorphism and pseudopolymorphism of WX-671is only possible after carrying out a polymorphism study.

WX-671 was dissolved in solvents (tetrahydrofuran, acetonitrile,methanol) of different polarity. The solutions were filtered, dividedinto four and the active compound was crystallized at different rates.After drying at room temperature, the thermograms (DSC, TGA) and theX-ray diffractograms were recorded.

The starting substance employed for the polymorphism screening could beprepared in mainly crystalline form. The crystallization was possiblefrom acetonitrile in the freezer at about −18° C.

Example 9

Differential Scanning Calorimetry (DSC) and Thermogravimetry (TGA) ofWX-671 (Free Base)

FIG. 16 shows the DSC and TGA thermograms of the amorphous startingsubstance. Just like the DSC/TGA thermograms of the greatest part of theother samples investigated, it shows a thermal effect in the rangebetween 45° C. and 85° C. It was not possible to assign this thermaleffect in the course of the polymorphism screening. It could be a glasstransition. Conclusions as to a crystal form having a melting point ofabout 190° C. could follow from this. Depending on the heating rate, thesubstance decomposes from about 155° C. For this reason, the meltingpoint of the crystalline sample (GBA 190903-8c) cannot be determined.The thermograms of the amorphous and crystalline substance are thereforelargely identical (FIGS. 16 and 17).

Example 10 Microscopy of WX-671 (Free Base)

WX-671 crystallizes from acetonitrile in the freezer in the form ofprisms (FIG. 18). The active compound does not crystallize or onlycrystallizes to a very small amount from other solvents; it does notcrystallize from the melt.

Example 11 X-Ray Diffractometry of WX-671 (Free Base)

FIG. 19 shows the X-ray diffractogram of the active compound aftercrystallization from acetonitrile in the freezer (modification A).

TABLE 11.1 X-ray diffractometry peak list for WX-671 (free base) Thesample was crystallized from acetonitrile in the freezer. WX 671Reflections 2 theta 3.2 5.5 6.4 8.5 9.7 10.2 10.7 11.2 11.5 11.7 12.113.4 13.8 14.1 14.6 14.8 15.5 16.5 18.1 19.1 19.7 20.5 20.7 21.3 22.422.7 23.6 26.5

Example 12 Moist Sorption of WX-671 (Free Base)

FIG. 20 shows the sorption isotherm of water vapor on WX-671 at 22° C.The amorphous active compound takes up water continuously from 0% r.h.to 95% r.h. On drying, this water is given off again. At most points ofthe isotherm, no equilibrium state was achieved within the respectivestopping time. The sample weight increased or fell further. There was noindication of hydrate formation in this experiment.

Example 13 Stability of WX-671 (Free Base)

By stirring in diisopropyl ether and ethanol/water (1:1) at roomtemperature for one week, the active compound does not crystallize orcrystallizes to a very small amount in modification A. It is notconverted to any other polymorphic form. It is likewise not converted bymechanical stress (grinding in a mortar, compressing at 9 kbar); thecrystallinity only decreases further.

1. A crystalline form ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide and/or a salt thereof.
 2. The crystallineform as claimed in claim 1, characterized in that it consists of acrystalline form ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide sulfate.
 3. The crystalline form ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide sulfate as claimed in claim 2, characterizedin that it essentially contains the following peaks according to anX-ray diffractometry analysis: 3.7 10.3 12.1 13.8 16.4 19.2 22.2.
 4. Thecrystalline form as claimed in claim 1, characterized in that itcomprises a crystalline form ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide hydrogen sulfate.
 5. The crystalline form ofclaim 1, wherein said salt ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide is a hydrogen sulfate and wherein saidhydrogen sulfate is characterized in that it essentially contains thefollowing peaks according to an X-ray diffractometry analysis: 4.3 10.120.2 21.4 24.0.
 6. The crystalline form ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide hydrogensulfate as claimed in claim 5,characterized in that it shows a decomposition from a temperature of175° C.-195° C. (DSC, heating rate 2 Kmin-l).
 7. The crystalline form asclaimed in claim 1, characterized in that it comprises a crystallinemodification ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide as a free base.
 8. The crystalline form asclaimed in claim 7, characterized in that it comprises a crystallinemodification ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide as a free base as a single crystal.
 9. Thecrystalline form ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide as a free base as claimed in claim 7,characterized in that it essentially contains the following peaksaccording to an X-ray diffractometry analysis: 3.2 6.4 10.2 19.7. 10.The crystalline form as claimed in claim 1, characterized in that itcontainsN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide and sulfate anions in a molar ratio of1.5-2.5:1.
 11. The crystalline form as claimed in claim 1, characterizedin that it containsN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide and hydrogensulfate anions in a molar ratioof 0.5 to 1.5:1.
 12. The crystalline form as claimed in claim 1,characterized in that it comprises units of in each case two moleculesofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide and a sulfate anion in differentconformations.
 13. The crystalline form as claimed in claim 1,characterized in that it contains between 2.5 and 3.5 moles of water permole of salt.
 14. A medicament comprising as active compound acrystalline form as claimed in claim 1, optionally together with apharmaceutically tolerable carrier or/and excipient, said medicament isan orally, nasally, inhalatively, rectally or/and parenterallyadministrable agent.
 15. The crystalline form as claimed in claim 10,wherein said molar ratio is 2:1.
 16. The crystalline form as claimed inclaim 11, wherein said molar ratio is 1:1.
 17. The crystalline form ofclaim 1, wherein two molecules ofN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide and a sulfate anion are present in one unitcell in different conformations.
 18. The crystalline form of claim 2,wherein saidN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide sulfate is a single crystal.
 19. Thecrystalline form of claim 4, wherein saidN-α-(2,4,6-triisopropylphenylsulfonyl)-3-hydroxyamido-(L)-phenylalanine4-ethoxycarbonylpiperazide hydrogen sulfate is a single crystal.